Encoding
encoding
text
characters
What is ASCII?
Definition
ASCII (American Standard Code for Information Interchange) is a 7-bit character encoding standard that maps 128 characters — including English letters, digits, punctuation, and control characters — to numeric values 0 through 127.
Why It Matters
ASCII is the foundation of nearly all modern character encodings. UTF-8 is backwards-compatible with ASCII, meaning any valid ASCII text is also valid UTF-8. Understanding ASCII is essential for working with encodings, binary data, and low-level string manipulation.
Frequently Asked Questions
How many characters does ASCII support?
Standard ASCII supports 128 characters (7 bits). Extended ASCII uses 8 bits for 256 characters, but the upper 128 vary by code page.